Page 195 - Parker - Quick Coupling Products

Valves

Multiple Hydraulic System Applications As oil is drawn from the reservoir and pumped to the circuit,
a vacuum is created in the reservoir. The vacuum relief valve
Parker Check Valves are unidirectional flow control devices opens to allow filtered air to enter. As oil is pumped back into
used primarily in hydraulic systems to eliminate potential the reservoir, air pressure builds. Additionally, as the oil heats,
damage caused by fluid back pressure. Offered in many the pressure inside the reservoir increases. When the pressure
configurations, Parker can satisfy most hydraulic system exceeds the relief valve setting, the excess pressure is vented
applications. Parker’s in-line style check valves are available in to atmosphere. Normally, the pressure will fluctuate between
a variety of sizes, pressure ratings, flow capacities and zero and the pressure relief setting without opening either
crack pressures. valve. This can significantly reduce the breathing of outside air
and minimize the chance for moisture and contamination to
enter.
H1, HM1 and PV Series Pressure / Vacuum Relief Valves are
used to create and maintain a positive pressure in hydraulic TH Series Thermal Bypass Valves ensure efficient equipment
tanks and reservoirs. These pressurized reservoir valves operation at any temperature. These valves are ideally
provide the following benefits: suited for hydrostatic drive circuits which require fast warm-
up, controlled fluid temperatures and low return line back
• Prevents pump cavitation by assuring a positive
supply of oil at the pump inlet pressure. When installed in a return line of a hydraulic
circuit that utilizes an oil cooler, this valve will modulate fluid
• Minimizes the tank breathing of outside, moist, temperature by either shifting return line flow through the
contaminated air cooler, or bypassing directly to the reservoir. An integral
• Filters all incoming air pressure relief function automatically releases excess pressure
to the reservoir if the cooler becomes restricted and the inlet
pressure becomes excessive.

E Valves

E-1 Parker Hannifin Corporation
Quick Coupling Division
Minneapolis, MN
www.parker.com/quickcouplings